Newbie here. just been given a old Hobie 14 with some serious damage to one of the hulls which I'm attempting to fix up. The worst are a couple of holes about 4-6" in size where the trailer ends punched into the hull during a typhoon.

I have been getting all kinds of great ideas on how to repair them from these forums, and the "this Old Hobie" articles on major repairs and blind repairs but there's one point I'm not sure on. I will be doing these as blind repairs. I will follow the method in the article on blind repairs - remove the damaged area of fiberglass - but once I have the backing laminate in place am I to layer glass up to thickness of the hull until it is flush with the exterior or use foam as in the original construction? Bear in mind the holes will likely be about a 6" diameter so they are substantial. Rick Buchanan advises this in his "Major Fiberglass Repairs" article but not in the blind hole repairs one...any pointers are very welcome before I get into it!

looks like your on the right track. As they say alot on this board "if its fiberglass it can be fixed". Since it appears these are impact puncture wounds I would make sure your inner skin is solid above all else. other than that I think you have it figured out. The holes appear to be small so it would be just as easy to fill it with polyester putty than it is to find and mess with Divinycell (only foam that will work with polyester resin). I don't think you will add enough weight to make a difference by using putty over divinycell based on what i see in the pictures. I can't stress enough to make sure all of the damaged inner layer is fixed and solid before you start building out.

Newbie here. just been given a old Hobie 14 with some serious damage to one of the hulls which I'm attempting to fix up. The worst are a couple of holes about 4-6" in size where the trailer ends punched into the hull during a typhoon.

Once you have the backer material iun pkace, I would build up the damaged area using woven roven glass then 4-6oz glass cloths. finish the last ( outer layer) with the light weight cloth . Use Vynalester resin. Stronger then Polyester but cheeaper than epoxy.

I have been getting all kinds of great ideas on how to repair them from these forums, and the "this Old Hobie" articles on major repairs and blind repairs but there's one point I'm not sure on. I will be doing these as blind repairs. I will follow the method in the article on blind repairs - remove the damaged area of fiberglass - but once I have the backing laminate in place am I to layer glass up to thickness of the hull until it is flush with the exterior or use foam as in the original construction? Bear in mind the holes will likely be about a 6" diameter so they are substantial. Rick Buchanan advises this in his "Major Fiberglass Repairs" article but not in the blind hole repairs one...any pointers are very welcome before I get into it!

Thanks for the reply, hadn't thought of using putty in place of foam. I've assessed the damage more thoroughly and there is delamination of the inner glass a couple of inches past the cracks/holes. I can cut out an oval shaped area which would take care of these sections and make a good area to work on building back up.

About the foam, if I wanted to go that way, it would be difficult for me to source divinycell (I live in Japan making things that extra bit complicated) but I have come across mention in the forum of EPP (Expanded Polypropylene?) being used also. Can anyone confirm/deny this as I can get hold of that from a local RC model shop.

I can't work on it this weekend as I had hoped (another typhoon is approaching - hopefully I won't have any more holes to repair after the weekend!!) which gives me more time to figure out my best plan of action...

There's a great article on this exact repair by Rick Buchanan in one of the more recent Hotlines. Someone knows which issue it's in. There's really no need to use expensive epoxy systems for this simple repair.

I would also suggest using foam core. You don't want to create a hard spot, which can potentially crack.